Ground clearance is the distance between any part of a vehicle (other than those parts designed to contact the ground, such as tires, tracks, skis, etc.) and the surface upon which the vehicle travels. Vehicle suspension systems maintain the distance between the axles of a vehicle's wheels and the other parts of the vehicle, and are usually designed to maintain a sufficiently high ground clearance to avoid obstacles anticipated to be in the vehicle's path, including (for example) to avoid scraping when going over a speed bump. Some vehicles, such as off-road vehicles, are designed with a high ground clearance to avoid obstacles encountered in rugged terrain, while other vehicles are designed with low ground clearance for high speed performance and/or sportier appearance. However, if the surface over which a vehicle travels has a speed bump, slope or other obstacle, then even if the distance between the vehicle's axles and other parts of the vehicle is maintained by the suspension system, the ground clearance at the ends or other parts of the vehicle may not be maintained, so that those ends or other parts may scrape that surface. A suspension system can use mechanical, pneumatic, hydraulic, magnetic, electronic, electro-magnetic, electro-mechanical or other means to support the weight of a vehicle and maintain the distance between the vehicle's axles and other parts of the vehicle. Conventionally, a suspension system is mechanical, and contains springs to provide a restoring force, and shock absorbers to provide a damping force, to restore the distance between the vehicle's axles and other parts of the vehicle after the vehicle encounters a bump or other obstacle. By contrast, a lift system is a system that increases the ground clearance when activated, and decreases the ground clearance when deactivated. A lift system can be used together with an active suspension system, that is, a suspension system that actively restores the distance between the vehicle's axles and the other parts of the vehicle when the vehicle encounters an obstacle, such as a bump. An active suspension system can be, for example, a system that senses an obstacle or change in the distance between the vehicle's axles and other parts of the vehicle, calculates an appropriate mechanical, hydraulic, pneumatic, magnetic or other restoring force or damping force or other force (in response to the sensed obstacle or sensed change in distance between the axles and other parts), and then applies that calculated force to the suspension system when the vehicle encounters the sensed obstacle or sensed change in ground clearance, to restore the distance between the axles and other parts. By contrast, passive suspension systems, such as conventional spring and shock absorber systems, do not sense obstacles or changes in distance between the axles and other parts, calculate forces in response to the sensed obstacle or sensed change in distance between axles and other parts, and then apply the calculated forces to the suspension system.
The benefits of low ground clearance and lower vehicle height are numerous and include less wind resistance, better fuel economy, better acceleration, better cornering, and better braking. Another significant advantage of low ground clearance is that it allows for better aesthetics such as providing a lower, sleeker, and sportier appearance that is desired by many drivers.
Many modern vehicles are designed and built with low ground clearance for the sportier appearance. Vehicle owners also lower their vehicles, through after-market modification, for enhanced performance, fuel economy and sportier appearance. One of the most common ways to lower a vehicle is through the use of a coilover, a vehicle suspension device that incorporates a coil spring positioned over and around a shock absorber shaft that is connected to a shock absorber body. Use of a coilover allows for a limited amount of height adjustment by adjusting the height of the coil spring's lower mounting point.
Other common ways to lower a vehicle include using shorter coil springs on the vehicle's suspension or adjusting the height or length of the suspension springs.
Reducing a vehicle's ground clearance height frequently results in undesired contact (collisions or scraping) between the vehicle and obstacles in the vehicle's path, such as speed bumps, sloping driveways and uneven surfaces. Unfortunately, when contact occurs, the vehicle is often damaged from the contact. Sometimes the obstacles are too large or too tall for the vehicle to travel over them. In the past, other vehicle lift systems have been developed, but they fall short of providing an adequate solution for many reasons. For example, some lift systems are designed and built to be vehicle-specific and are not readily adaptable to other vehicles. On the other hand, lift systems designed to fit a variety of vehicles often require the removal or replacement of existing components, resulting in added costs for the replacement components and loss of performance from the removal of critical or beneficial existing components. Such removed components may include coil springs, dust sleeves and bump stops.
Some prior art lift systems employ pressurized rubber air bags or air sleeves to replace coil springs in a suspension system. These systems do not retain the performance characteristics and benefits of metal coil springs, and incur the added cost of replacing the existing shock absorbers and/or metal coil springs with air bags or air sleeves. Moreover, components in lift systems that use metal coil springs may be so tall or thick that they do not fit into vehicles with the existing suspension springs. In such cases, the coil springs must be replaced with shorter springs resulting in a loss of suspension performance from the shorter spring.
Some prior art lift systems use hollow double-walled cylinder designs having concentric inner and outer cylinder walls. This design is complicated, more costly to manufacture, and more difficult to protect against dust and contaminants. These systems are also less efficient in the use of stored air pressure. They also have reduced pressurized surface areas on which the pressure to the piston can act, resulting in inefficient use of power and the need for a larger storage tank to hold the compressed air (or other fluid), which is used to lift the vehicle. The tank required may reduce useable storage space, or even be so large that it cannot fit into many vehicles in a practical manner, and therefore is not able to be used in those vehicles.
It is a further object of the present invention to eliminate or reduce the effects of environmental contaminants and the damage they cause to lift system components. Lift system components are typically installed near the vehicle's suspension system's coil springs and the tires. The lift system components are typically exposed to environmental contaminants such as dust, water, mud, sand or snow.
Prior art lift systems with cylinder and piston actuators that are positioned around the coil springs, and that have exposed cylinder bores, are susceptible to damage caused by such environmental contaminants. While the damage to the cylinder bores and the piston-bore seals is an obvious problem, an effective solution for protecting these components from environmental contaminants has not been obvious. Developing a solution for protecting the cylinder bores from environmental contaminants has been problematic because: 1) the cylinder bores are adjacent to a moving coil spring, and 2) because a piston must be able to slide within the cylinder bore without restriction, and 3) because the space for the cylinders is limited, and 4) the cylinders are frequently located near a spinning tire that may move and turn as the vehicle is operated. These space constraints and moving elements impose many design limitations that prevent the use of many conventional solutions that would otherwise be suitable to protect the cylinder bore.
For example rubber bellows would not be an effective solution for sealing around an active and long coil spring. Even if a rubber bellows were to be used, it would be bulky and it would introduce another component that would be subject to wear and deterioration and it would introduce additional problems.
Prior art vehicle lift systems with cylinder and piston actuators that are positioned around the coil springs, such as those used by Umbrella Auto Design, Roberuta, Phantom VIP, Fortune Auto Muller and Stance-Solutions do not provide protection from environmental contaminants to their cylinder bores. They all use exposed and unprotected cylinder bores with the problems described above.
Prior art vehicle lift systems with cylinder and piston actuators that press against a coil spring are prone to misalignment of the piston within the cylinder bore because the coil spring exerts uneven forces upon the piston. The spring pressure against the lift system's piston is uneven for many reasons such as off-centered springs or movement of the suspension system. In some cases, the springs could be mounted off-centered relative to the piston, as shown in FIGS. 17 and 18. The uneven spring pressure against the lift system's piston causes uneven forces upon the piston and this can result in the piston tilting or moving off center (mis-alignment) within the cylinder bore.
In prior art, the tilting of the piston can result in the piston rubbing against the cylinder bore and causing damage to the cylinder bore and to the piston-bore seal(s). In extreme cases, the piston can tilt enough to become seized within the cylinder bore.
In prior art lift systems, the pistons are made longer than would otherwise be necessary to reduce tilting or misalignment of the piston within the cylinder bore. The pistons are cylindrical with piston-bore seals at the top of the piston and at the bottom of the piston. The pistons are relatively long with seals at the top and the bottom of the piston in an attempt to reduce the tilting or misalignment of the piston and the resulting damage and malfunctions that could occur. In these prior art lift systems, increasing the length (height) of the piston helps to reduce damage to the cylinder bore, however it reduces the effective stroke or length of travel within a cylinder of a given length. These relatively long pistons usually require the use of shorter coil suspension springs to offset the added piston height. The use of shorter coil springs reduces the suspension's travel and performance.
Prior art lift systems that use bump stops, typically do so in a manner that reduces the effective pressurized area above the bump stop, making the system less efficient and requiring more air pressure and/or stored pressurized air to operate properly. They also do not provide a means for having the bump stop travel in tandem with the piston without touching and causing any wear upon the shock absorber rod.
Some other prior art systems use hydraulic pumps and pressurized liquid to raise the vehicle, and use hollow, double-walled cylinders having concentric inner and outer walls. This type of system is less efficient and requires significantly higher operating pressures to be effective. Hydraulic systems also require more costly hydraulic pumps and/or tanks filled with heavy hydraulic fluid and have the risk of fluid leaks and/or oil spills.
Hydraulic systems typically use cylinder and piston assemblies that are relatively thick (tall) positioned on the top or bottom of the coil spring. They add considerable height to the spring and usually require the use of shorter coil springs. Using shorter coil springs normally results in a reduction of suspension travel and reduced suspension performance.
Hydraulic systems also pump fluid only when it is needed to lift a vehicle. Thus, they are slower acting systems that require strong pumps to raise a vehicle with enough speed to be effective. They draw higher amperage on a vehicle's electrical system. Further, because hydraulic systems typically raise vehicles slowly, they are not practical to use in many driving situations.
Prior art lift systems also do not have an adjustable, automated activation system that automatically senses obstacles in a vehicle's path and raises or lowers the vehicle based on the vehicle's proximity to the obstacles and its speed.
Other lift systems use components, such as large pneumatic cylinders or large air tanks that are often too large to install into many vehicles. These larger components also add undesirable weight to the vehicle, thus decreasing vehicle performance and efficiency.
Other systems that use compressed air tanks may also allow condensation (water) in the air tank to be passed through the air outlet port under certain driving conditions, which may cause surges of the water (surge water). Examples of such conditions include acceleration, braking and cornering. The surge water that passes through the air lines to the valves, pressure sensors, cylinders and other components has detrimental effects on these components.
Prior art lift systems include: Umbrella Auto Design, Roberuta, Phantom VIP, Fortune Auto Muller, Stance-Solutions, Top Secret, Mode Parfum, Skipper, KW Hydraulic Lift System, Tech-Art, Ram Lift Pro, AirForce, AirRex, Air Lift, and Accuair.
It is an object of the present invention to provide an affordable lift system that is adaptable to a large variety of vehicles.
It is another object of the present invention to provide an efficient lift system that only requires small pressurized cylinders and storage tanks and to provide increased piston travel (stroke) within a cylinder of a given length to provide increased lifting capabilities while using shorter cylinders.
It is another object of the present invention to provide a lift system that adds only a small amount of height to the coil spring.
It is another object of the present invention to provide an effective means to eliminate wear and damage to cylinder bores caused by contact of the pistons with the cylinder bores by eliminating contact of the pistons with the cylinder bores.
It is another object of the present invention to provide an effective means to control the tilting of pistons in cylinder bores of lift systems and to eliminate the problems associated with the tilting of pistons in cylinder bores of a lift systems.
It is another object of the present invention to provide an effective means to eliminate wear and damage to cylinder bores and to piston-bore seals caused by environmental contaminants.
It is a further object to provide means for operating the system in safe manner that does not require the driver to take his eyes off the road (to look for and operate switches), and to make the operation of the system automatic and hands-free.
It is a further object to provide an effective means to automatically adjust the height of a vehicle to provide adequate ground clearance to traverse over obstacles in the vehicle's path.
It is still a further object to overcome the drawbacks relating to the prior art devices discussed above and to provide at least some of the benefits described below.